Pneumatic tire and process of making the same



W. B. PRATT.

PNEUMATIC TIRE AND PROCESS 0F MAKING THE SAME.

APPLlcATmN FILED JAN.3, i919.

1,349,91 3, y Patented Aug. 17, 1920.

Lam/nde qf rubber and co/daffbr/b 'v @Wmw orne'ys nantais.h

UNITED Sumter orme.

. WILLnm Buon rum, or wELLEsLEr, MASSACHUSETTS, nsszanon man, H, um v BBBER COIPANY, I' BOSTON, MASSACHUSETTS, A CORPO GHUSETTS.

To all-(whom it may concern:

so-called carcass protecting the fibers 'the fabric, prior to Beit known that tI, Wim-misa BEACH PnATr, a citizen of the United States residing at Wellesley Y the county of orfolk and State' of Massachusetts, have invented new and useful Improvements in v Pneumatic-Tires and-Processes of- Making the Same, of which the following is a specication. V

This invention relates to pneumatic' tires of those classes in which the tire constitutes an endless tube which may itself be inflated, or in which an outer and protective shoe is inflated by means of an inner tube, and also relates to the process of making the same.

The common practice in either case, in the construction of 'the tire, is to form a 4or base of Afabric or cord which forms al wall or support on which the rubber tread maybe vulcanized. The base or' carcass is then completely inclosed within aV layer of rubber for the protection of the side Walls, and, by increasing the thicknessl of the layer -at the periphery of the circular carcass, a rubber tread is produced for taking the wear.

Because of the impossibility of properly of the fabric or cord to prevent oxidation thereof, it has been found necessary to protect the fabric so far as may be by suitable rubber structures. When these rubber structures are broken through or are Worn down to the fabric of the carcass, the fibers of the fabric or cord absorb moisture, rot and oxidize, so that in common practice, as has been stated, it has been the object to place on all pneumatic tires suitable rubber treads to protect this carcass, and hence the life of the tire has largely been de pendent on such rubber coating. In lthe practical construction of pneumatic tires, the vulcanization of the built-up structure is frictioned That is, a bbdy of rubber compound is mechanically worked into the interstices of the cloth by suitable instrumentalities, and the cloth so frictioned is formed with intervening layers of rubber compound into a laminated structure.

I .have found'it possible to treat the fabric or cords heretofore used in tire construction in such wise as adequately to, protect them against oxidation, rottin and disintegration, This is accomplishe by impregnating murarie 'rien ND ritoci'essA or Mame 'nin spwmmm of Letten ratent. Q Application led January 3, 1919. `Serial canized thereto or this tendency to arubber compound approaches with a relatively Barron or russa.

. Patented Aug. 17, 1920. iro. seam v themA with -a non-colloidal sulfuriterpene compound, which'has the added advanta e that 1n vulcanization'it willunite' with'ru ber. By treating the materials of which the carcass ismade with the said com ound, it

ilas possible greatly to prolongthe life of the ire. f

This compound, being non-coloidal,` l v the property of penetrating the individual rs,V and, when the vulcanization of the entire structure is effected, the contiguous fabric cannot b junction.

There is a chemical reaction between the rubber compound and the sulfur compound with which the fabric is treated and per meated, and a bond or union is thus created between theibers and the vulcanized rubber. A l pneumatic tire, comprising the fabric conditioned or treated as stated and rubber vultherewith, constitutes a generic feature of -poundsv willin time oxidize to a point of self destruction, and that the period of use in the arts of such compounds is limited by oXidization or rotting. And known that the more nearly crude rubber and sulfur only, the more readily does' it rot, so that the. most resilient and elastic vulcanized rubber compoundsstend to oXidize or disintegrate more rapidly than coinpounds of higherv specific gravity and of less resiliency and stretch.

Consequently by the commercial practice of inclosing the carcass in the resilient tread it is equally well layer, it has been necessary to employ rub ber compounds of high specific gravity (i. e.

large proportion of litharge or other equivalent material) to offset by increased durability the loss of resilienc in the tread.

aving lascertained that itlis possible to greatly retard, if not entirel prevent, the rotting and oxidation of the fabric forming the carcass by its impregnation or treatment with the non-colloidal sulfur-terpene compound, I now find that itis also possi.

my invention irrespective of the particular -form or structure of the tire, or the arrangement of the carcass in the tread, and to incluse ble, 4as a subsidiary feature of my invention, to reverse the usual :tire by forming the carcass on the outside of the tire to .constitute therein the rubber bod and thus to use a more highly resilient rub er compound in the construction of the latter. That is, I dnd that, by formin the tread of the treated layers of woven fa ric,

cord, or the like, and thereby inolosing the resilient rubber bodA of the tire, the bod is Aitself protected an may consist of hig ly resilient and hence qulckly oxidizable or easily rotted rubber compounds. Thus I am able to provide a tire which is not onlymore durable than those heretofore commercially produced but( which is more elastic and resilient. The carcass thus becomes the protective coating or tread of the tire A insteadof being placed -on the inside as the supporting wall of the tread.v

. On the accompanying drawing, Ffigure 1. shows in cross section-a pneumatic tire shoe,

which will serve as an illustration of one embodiment of my invention, and by the term tire I mean to include closed tubular pneumatic tires, shoes and other formsof pneumatic tires which are themselves in- Hated or inclose an inlatable tube. Fig. 2 shows in cross-section a pneumatic tube tire. A- suitable neutral amorphous non-colloidal sulfur-terpene compound may be produced by digestin oil o turpentine or its vequivalent w1th su fur at atmospheric ressure and at a temperature of 140"v or above, asexplained in my copending application Serial No. 328,235, filed October 3, 1919. The reaction is pro essive, and the product may be either so 1d or semi-solid when cooled. The duration of treatment deto which pends upon the temperature and the extent digestion. -lWhen the reaction isl carried to completion, the product on'coling to ordinary temperatures is a hard black solid, breaking with a conchoidal fracture and eX- hibiting a vitreous luster 'on the surface of the fracture. It is neither acid nor alkaline, is insoluble in water, partly soluble in acetone, Dsoluble withreaction in turpentine, and soluble in toluol and Xylol. The solid and semi-solid products when liquefied with heat, Vor when pable of assing through parchment, .and thus, by rahams test, are non-colloidal. As previously stated, thls non-colloidal sulfur-terpene compound has the propertyof penetrating the canal offa hollow ibei', e. g. cotton, an of permeating the wall thereof,

and also, under a vulcanizlng temperature,

with a rubber-sulfur compound.

of reacting of the present invention,

In the practice .the fabric, such as cotton cloth, is'treated "with a solution of vthe said non-colloidal vess of its production, however that the invention yas the material is agitated during the.l

dissolved in a solvent are cai theatre or inclosedfan molds, and the structure is vulcanized under thejrequisite conditions of pressure and 'temperature'.

Se far Ias'the present invention is concerned, they particular fabrics used, c. woven'strips, Icords orthe'like, vare of no particular moment, so long as the7 are properly impregnated'or treated an protected ound, nor is it necessary that an articu- `ar procedure be followed in buil ing the tire, provided that the proper results are secured; but, in order that one example of tire may be explained, I shall describe the procit being understood defined in the claims is not limited thereto.

0n a suitablel form, I stretch or wrap, in the usual manner, a layer 1 of woven fabric, e. g. linen, jute, hemp, cotton o r duck, on which I paint a thick coat of the sulfurterpene compound dissolved in a volatile solvent, so that the `com ound will not only coatit, but thorough y im regnate and saturate the bers thereof. he setting of the compound may be expedited by the application of moderate heat to drive olf the solvent. If desired, the fabricmay be impregnatedor treated before it is placed on the form. In fact, the fabric is preferably passed through a bath of the solution, and the solvent is evaporated, before into 'the tire: The treated fabric may be frictioned as usual, with any suitable friction, e'. e. sulfur and rubber with any of the usual compounding materials. Next I build o n the form a rubber body 2 of rubber compound-.which is of low specific gravity and is highly elastic and resilient when vulcanized. This bodyis thickest at the crown or top proceed to build zon the layers which form the protective carcass 3, These are alternate layers of cord, or woven fabric and thin rubber, the fibrous materials having been impregnated or treated with my noncolloidal sulfur-terpene compound, until the carcass of the desired thickness is formed. In the case of the shoe, the rings 4 of higher gravity rubber compound are enwrapped in the la ersto form the beads 5, and finally over t e whole is placed a thin envelop 6 of rubber compound. rI-*he tire thus formed i's.

placed in a mold of suitable lform where it is subjected to the requisite amount' of pressure, and to a vulcanizing temperature for thedesired period of time. In'the process of vulcanization, the sulfur-terpene compound vulcanizes onto the' rubber, and a tire such as shown in the drawing is produced.

.While I have thus described a particular form of tire possessing advantages due to its it is builtY by the non-colloidal sulfur-terpene comand tapers toward the edges. Then i novel construction, my invention is not limited thereto except as specified in certain of the appended claims, since the invention broadly considered comprises a tire in which the fabric is strengthened and protected by the non-colloidal sulfur compound, and is bonded to the contiguous vulcanized rubber during the vulcanizing process.

A tire thus formed, irrespective of its particular construction, is better able to withstand the various different strains and flexings to which it is subjected in ordinary usage than a like tire in which the fabric was not conditioned or treated as herein described. Instead of the usual relatively weak and non-uniform adhesion secured between the frictioned fabric and the conti uous vulcanized rubber, which permits, un er tension and flexing, water or air to enter between the layers of which the tire is formed, a tire embodying the present invention has the fabric so bonded to the fibers of the fabric by the reaction between the rubber compoundl and the sulfur-terpene compound that the penetration of water and air, even when the fabric layers are more or less Worn through, is negligible.

The individual tire manufacturer will, of course, produce tires of any desired forms or shapes to suit the needs or desires of his customers, this being also true as to the exterior formation of the outer surface of the tread.

Under certain circumstances, the layer of fabric, which constitutes the inner wall of the tire, may be omitted, especially in the construction of continuous tube inflatable tires.

F or-'example in Fig. 2 I have shown a tubular tire in which the inner rubber body 7 of resilient rubber is inclosed within and bonded to a carcass 8 consisting of laminae of rubber compound and Aconditioned or treated fabric. n

The fabric (woven strips or cords, as the case may be) of which there may be as many layers as may be desired is first conditioned or impregnated with the neutral amorphous noncolloidal-sulfur compound in solution and the solvent evaporated, and after the structure is formed in any usual or suitable way, is subjected to vulcanization.

I do not herein claim the herein described non-colloidal sulfur terpene compound or the process of making it `as these form the subject matter -of my said application, Serial No. 328,235, or a fabric conditioned or treated as herein described, since this is claimed in my application Serial No. 278,228 filed January 8, 1919; or broadly a product consisting of rubber and said fabric vulcanized together. c

-Havingkthus explained the invention, and described several forms of tires and certain ways of practising the process, Without attempting to describe all the various tires in which my invention may be embodied or all of the Ways in which my invention may be practised, what I lclaim is l1 A method of making pneumatic tires which consists in treating a fibrous material with a non-colloidal sulfur terpene compound, forming the tire structure of rubber and said treated fibrous material, and vulcanizing said structure.

2. A method of making pneumatic tires, which consists in treating a fibrous material with a non-colloidal sulfur-terpene compound, formingthe tire structure of layers 'of rubber compound and said treated fibrous material, and then vulcanizing the structure. 3. A method of making pneumatic tires,

`which consists in treating fibrous material with a non-colloidal sulfur-terpene compound, building about a body of rubber compound a protective outer carcass or tread of laminas of rubber and said treated fibrous material, and then vulcanizing the structure thus formed under suitable conditions of heat and pressure.

4. A pneumatic tire consisting of a structure of rubber and fibrous material, the fibers of said fibrous material having been permeated with a non-'colloidal sulfur-terpene compound, all vulcanized together.

5. A pneumatic tire comprising layers of rubber and of fabric treated w1th a noncolloidal sulfur-terpene compound, vulcanized together.

6. A pneumatic tire comprising layers of rubber and an intervening woven fabric impre nated or treated with a non-colloidal sul ur-terpene compound, all vulcanized together.

7. A pneumatic tire com rising an inner hollow resilient rubber body and an outer protective tread carcass of rubber and fibrous material, the whole being vulcanized together, and said fibrous material having been impregnated with a non-colloidal sulfur-terpene compound.

In testimony whereof I have affixed my signature.

WILLIAMA BEACH PRATT. 

